The Mercedes Eco Start/Stop system can malfunction for various reasons, but a common culprit is an inadequately charged battery. This could be either the main starter battery or the auxiliary battery (often a capacitor in Mercedes vehicles). Typically, these batteries recharge during highway driving. However, even with overnight drain, the battery should recharge while driving.
A trickle charger (like a CTEK) can be used to fully charge the main battery to see if this resolves the issue. If not, one or both batteries might require replacement. Utilizing Mercedes’ STAR diagnostic system or having the main battery load-tested can pinpoint the problematic battery. The STAR system can also identify unrelated faults affecting the Start/Stop function. However, if the faulty battery isn’t clear, replacing the auxiliary battery first, and then the main battery if the problem persists, is a recommended approach.
Alternatively, if the Start/Stop malfunction doesn’t impact other vehicle functions, continuing to drive without replacing the battery is possible. The battery might still have considerable life left, providing reliable service for months or years. Many drivers disable the Eco Start/Stop feature anyway, preferring a consistent driving experience.
A Mercedes battery connected to a charger. Properly charging your battery may resolve Eco Start/Stop issues.
The Eco Start/Stop indicator on a Mercedes dashboard. If this light is illuminated or behaving erratically, it indicates a potential problem with the system.
